1. Field of the Invention
This invention relates in general to current supply branching systems for separating signal and supply currents particularly for current supply of remotely fed line amplfiers.
2. Description of the Prior Art
The current supply for D.C. series-fed line amplifiers are known as shown, for example, in German Pat. No. 1,272,466 and such circuits include series connected high and low pass filters which are connected in series in the input and output sides of the line chokes. In such structures as illustrated in applicant's FIGS. 1a and 1b, the high pass coil is in the parallel branch and is connected in parallel to the input of the line choke D.sub.r and is connected in series with a capacitor C.sub.1 between the inner and outer conductors of the coaxial feed line. On the output side of the line choke D.sub.r is connected the repeater amplifier circuit V which contains a load resistance R.sub.V. At the connection point between the capacitor C.sub.1 and the high pass coil L.sub.1 one side of a low pass coil L.sub.2 is connected and the other side is connected by way of a capacitor C.sub.2 to the outer conductor of the input coaxial feed line. The other side of the capacitor C.sub.2 is connected to the load resistor R.sub.V of the repeater circuit V.
FIG. 1b illustrates a modified form of the prior art system of FIG. 1a wherein the low pass coil L.sub.2 has been incorporated into the winding L.sub.D of a line choke in the arrangement shown. The high pass coil L.sub.1 is required in this arrangement for proper operation of the circuit of the prior art.
In these known circuits for current supply branching, the high pass parallel inductance is always necessary for the direct current supply to the load resistor of the amplifier.